Wood Threads.skp (266.4 KB)
I managed to make something but it isn’t solid and won’t trim or intersect faces, so the nut doesn’t have threads yet.
The bottom face of the thread component is reversed and there’s a bunch of problem geometry that needs to be dealt with. You have SketchUp Shop so you have Solid Inspector and could use it to identify problems.
I will keep working on it. I did use Go Inspector. It showed one border hole, lots of short edges and a few nested components. It highlights them in red. I followed instructions by erasing lines and redrawing them to no avail. I will try again by copy/moving parts from above or below that have the same alignment with the center and replacing to see if I can make holes or nested components go away.